[Predator] Fix bug in min_distance after refactor and add back skip added/deleted deps.

appengine/findit/crash/culprit.py

 # Copyright 2016 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 from collections import namedtuple
 
-# TODO(http://crbug.com/659346): We do call this code from various
-# unittests, just not from culprit_test.py; so we need to add some extra
-# unittests there.
+
 class Culprit(namedtuple('Culprit',
-    ['project', 'components', 'cls', 'regression_range', 'algorithm']
-    )): # pragma: no cover
+    ['project', 'components', 'cls', 'regression_range', 'algorithm'])):
   """The result of successfully identifying the culprit of a crash report.
-  
+
   Args:
     project (str): the most-suspected project
     components (list of str): the suspected crbug components.
     cls (list of ??): the suspected CLs.
     regression_range (tuple): a pair of the last-good and first-bad versions.
     algorithm (str): What algorithm was used to produce this object.
   """
   __slots__ = ()
 
   @property
@@ skipping 69 matching lines @@
     """
     # TODO(wrengr): will this auto-dropping of unnecessary fields cause
     # any issues for JSON serialization?
     result = {}
     result['found'] = (
         bool(self.project) or
         bool(self.components) or
         bool(self.cls) or
         bool(self.regression_range))
     if self.regression_range:
+      assert isinstance(self.regression_range, list)
       result['regression_range'] = self.regression_range
-    if self.project is not None:
+    if self.project:
       result['suspected_project'] = self.project
-    if self.components is not None:
+    if self.components:
       result['suspected_components'] = self.components
-    if self.cls is not None:
+    if self.cls:
       result['suspected_cls'] = [cl.ToDict() for cl in self.cls]
 
     tags = {
       'found_suspects': bool(self.cls),
       'has_regression_range': bool(self.regression_range),
       'found_project': bool(self.project),
       'found_components': bool(self.components),
       'solution': self.algorithm,
     }
 
     return result, tags